The use of Lightweight Deflectometers (termed LWDs in Europe, and occasionally
PFWDs in the USA) for construction quality control or material investigation for road construction
has increased worldwide. In the UK the change in pavement foundation design to a
‘performance based approach’ has brought about the use of Lightweight Deflectometers for
field assessment of stiffness modulus. This paper reviews the LWD as a field evaluation tool. It
discusses in some detail the test variables that can influence and affect the field data quality, and
presents brief summaries of recent fieldwork where an LWD has been used as a quality control
tool. The paper concludes both on the LWD usefulness and also its limitations for a variety of
earthwork and road assessment scenarios, and describes a field test protocol for its use on a variety
of materials. The findings demonstrate the flexibility of the LWD but also show that its determination
of ‘stiffness modulus’ may differ from that of the conventional Falling Weight Deflectometer
(FWD) to a varying extent. The paper provides a useful reference document for
LWD users, consultants, material specifiers, contractors and clients.

Description:

This is a conference paper. Further details of the publication are available at: http://www.crcpress.com/product/isbn/9780415871990